Through his company Berkshire Hathaway, Warren Buffett has acquired two solar power plant projects from solar panel manufacturer and developer SunPower for between $2 billion and $2.5 billion.

Berkshire Hathaway’s energy subsidiary, MidAmerican Energy, has a stake in many of the largest US solar power plants, including two First Solar plants. Buffett has increasingly become an important ally for the renewable energy industry, which is struggling to survive without government financial support.

The newly acquired plants are located in California, and they are the world’s largest photovoltaic solar developments, meaning they use solar panels to convert sunlight into electricity. SunPower will retain the three-year contract to build and maintain them in the counties of Los Angeles and Kern. The Antelope Valley projects will generate 579 megawatts for Southern California Edison, which is not far off the output of a large fossil fuel power plant.

SunPower, based in Silicon Valley, will operate the projects for MidAmerican Renewables, a division of MidAmerican Energy.

“We are excited about these projects because they support our core business principle of environmental respect,” Bill Fehrman, president of MidAmerican Renewables, said in a statement. “We are very proud to add SunPower technology to our portfolio of projects.”

As The Street reports, market leaders like SunPower and First Solar are winning contracts to maintain large plants with multi-decade purchase agreements over their lifespan. By acquiring the plants, MidAmerican Energy has become one of the biggest backers of such projects.